The relative contribution of androgens and insulin in determining abdominal body fat distribution in premenopausal women

Molecular Assessment of Proadipogenic Effects for Common-Use Contraceptives and Their Mixtures

Hormonal contraceptives are widely prescribed due to their effectiveness and convenience and have become an integral part of family planning strategies worldwide. In the United States, approximately 65% of reproductive-aged women are estimated to be using contraceptive options, with approximately 33% using one or a combination of hormonal contraceptives. While these methods have undeniably contributed to improved reproductive health, recent studies have raised concerns regarding their potential effect on metabolic health. Despite widespread anecdotal reports, epidemiological research has been mixed as to whether hormonal contraceptives contribute to metabolic health effects. As such, the goals of this study were to assess the adipogenic activity of common hormonal contraceptive chemicals and their mixtures. Five different models of adipogenesis were used to provide a rigorous assessment of metabolism-disrupting effects. Interestingly, every individual contraceptive (both estrogens and progestins) and each mixture promoted significant adipogenesis (eg, triglyceride accumulation and/or preadipocyte proliferation). These effects appeared to be mediated in part through estrogen receptor signaling, particularly for the contraceptive mixtures, as cotreatment with fulvestrant acted to inhibit contraceptive-mediated proadipogenic effects on triglyceride accumulation. In conclusion, this research provides valuable insights into the complex interactions between hormonal contraceptives and adipocyte development. The results suggest that both progestins and estrogens within these contraceptives can influence adipogenesis, and the specific effects may vary based on the receptor disruption profiles. Further research is warranted to establish translation of these findings to in vivo models and to further assess causal mechanisms underlying these effects.

Correlations between serum testosterone and irisin levels in a sample of Egyptian men with metabolic syndrome; (case-control study)

BACKGROUND

Metabolic syndrome (MetS) in men is a common problem. Several studies highlight that testosterone deficiency is associated with metabolic disorders that may be explained by "myokines". Irisin is an adipo-myokine that has beneficial metabolic effects.

AIM

To evaluate serum testosterone in a sample of Egyptian men with MetS diagnosed by NCEP ATP III, and correlate it with serum irisin level.

METHODS

A total of 90 men (60 with MetS and 30 healthy age-matched controls) participated in the study. Testosterone level is estimated by an automated system, Irisin level was measured by ELISA.

RESULTS

Circulating irisin was positively correlated with serum testosterone and was significantly lower in patients with MetS.

CONCLUSION

This study highlights the effect of serum testosterone on irisin formation from skeletal muscle. Recommendations; treatments of MetS may include testosterone supplementation. Further studies are needed to elucidate this association.

Effects of aerobic exercise on plasma lipoproteins in overweight and obese women with polycystic ovary syndrome

Background:

Polycystic ovary syndrome (PCOS) is one of the most frequent endocrine disorders. The PCOS manifest by hyperandrogenism, hypertension and cholesterol and lipoprotein improper profiles. Changing the life style, e.g. increasing physical activities is the first approach in controlling PCOS.

Materials and Methods:

Twenty-four women affected by polycystic ovary syndrome (PCOS) after medical screening were divided in to two groups: Experimental group (n = 12) and control group (n = 12), with the average age, weight, height, BMI and WHR of 26.87 ± 4.43 years, 75.71 ± 10.65 kg. 159.29 ± 6.44 cm, 29.86 ± 3.22 kg/m² and 91.75 ± 5.86 respectively. First the body composition such as BMI, WHR, percent body fat, weight and body fat mass were measured. In fasting blood samples the level of HDL, LDL, VLDL, triglyceride and cholesterol were measured. Then the experiment group underwent the effect of an aerobic exercise program. After 12 weeks, all the measured variables before intervention the test were re-measured. Correlated t-test was used for comparing the two groups before and after intervention the test and independent t-test was used for comparing the two groups (P < 0.05).

Results:

The results showed that after 12 weeks of exercise, BMI, WHR, fat rate, weight and fat mass and triglyceride had significant reduction and HDL had significant increase. But no significant changes happened in LDL, VLDL, and cholesterol levels.

Conclusion:

Reducing the weight by aerobic exercise in obese women and affected by PCOS can correct lipoprotein profile and improving health.

Testosterone supplementation therapy in the treatment of patients with metabolic syndrome

Metabolic syndrome (MetS) comprises a clinical complex of patient risk factors, including increased waist circumference, high triglyceride levels, low high-density lipoprotein cholesterol level, high blood pressure, and insulin resistance, the presence of which increases the likelihood of developing diabetes and cardiovascular disease. With a quarter of the American adult population affected, MetS and type 2 diabetes mellitus have been referred to as the most significant public health threats of the 21st century. Lifestyle modification and weight loss are recommended, however, no specific pharmacologic treatment is known. Given that low levels of testosterone have been implicated in the pathogenesis of MetS and an inverse relationship exists between circulating testosterone levels and the development of MetS, it is tempting to speculate that men with MetS may benefit from testosterone supplementation therapy. As such, our review examines the role of testosterone and the use of testosterone supplementation therapy as a treatment in men with MetS.

Effect of exercise intensity on weight changes and sexual hormones (androstenedione and free testosterone) in female rats with estradiol valerate-induced PCOS

Introduction

Weight gain and fat accumulation are predisposing factors of PCOS. Life-style modification, including increasing physical activity, is the first line approach in managing PCOS. The objective of this study is to assess the effect of exercise intensity on weight changes, androstenedione and free testosterone level in female rats with estradiol valerate induced PCOS.

Method and materials

40 female Wistar rats were selected (180 ± 20 g). They had every 2 to 3 consecutive estrous cycles during 12 to 14 days. The study was approved by ethical committee of Jahrom University of Medical Sciences. The first two groups were divided into control (n = 10) and polycystic (n = 30) that were induced PCOS by estradiol valerate injection after 60 days. The polycystic groups were divided into three groups of sham (n = 10), experiment group with low-intensity exercise (pco + l.exe) (n = 10) and experiment group with moderate intensity exercise (pco + m.exe) (n = 10). Exercises were performed during 6 sessions of 60 minutes per week for 8 weeks. (Moderate intensity: 28 m/min-70%–75%VO2Max. Low intensity (20 m/min-50%–55%VO2Max) running at 0 slope, 1 h/day, 6 days/week). ANOVA and LSD test were used for data analysis.

Results

In the present study, no significant differences were found in the decrease of total weights of rats. And also androstenedione level changes in experiment groups were higher compared to control group but no significant differences were found, also free testosterone level was significantly higher than the observer group.

Conclusion

According to weight changes and sexual hormones (Free testosterone and androstenedione) exercise training especially with low intensity may improve symptoms of polycystic ovary syndrome.

Effects of gastric bypass surgery on female reproductive function

CONTEXT

Reproductive function may improve after bariatric surgery, although the mechanisms and time-related changes are unclear.

OBJECTIVE

The objective of the study was to determine whether ovulation frequency/quality as well as associated reproductive parameters improve after Roux en Y gastric bypass surgery.

DESIGN

This was a prospective cohort study that enrolled female subjects from 2005 to 2008 with study visits at baseline and then 1, 3, 6, 12, and up to 24 months after surgery.

SETTING

The study was conducted at an academic health center.

PATIENTS

Twenty-nine obese, reproductive-aged women not using confounding medications participated in the study.

MAIN OUTCOME MEASURES

The primary outcome was integrated levels of urinary progestin (pregnanediol 3-glururonide) from daily urinary collections at 12 months postoperatively. Secondary outcomes were changes in vaginal bleeding, other biometric, hormonal, ultrasound, dual-energy x-ray absorptiometry measures, and Female Sexual Function Index.

RESULTS

Ninety percent of patients with morbid obesity had ovulatory cycles at baseline, and the ovulatory frequency and luteal phase quality (based on integrated pregnanediol 3-glururonide levels) were not modified by bariatric surgery. The follicular phase was shorter postoperatively [6.5 d shorter at 3 months and 7.9-8.9 d shorter at 6-24 months (P < 0.01)]. Biochemical hyperandrogenism improved, largely due to an immediate postoperative increase in serum SHBG levels (P < 0.01), with no change in clinical hyperandrogenism (sebum production, acne, hirsutism). Bone density was preserved, contrasting with a significant loss of lean muscle mass and fat (P < 0.001), reflecting preferential abdominal fat loss (P < 0.001). Female sexual function improved 28% (P = 0.02) by 12 months.

CONCLUSIONS

Ovulation persists despite morbid obesity and the changes from bypass surgery. Reproductive function after surgery is characterized by a shortened follicular phase and improved female sexual function.

Testosterone and metabolic syndrome: The link

Metabolic syndrome (MetS) or "Syndrome X" which is a constellation of insulin resistance, hyperglycemia, hypertension, low high-density lipoprotein cholesterol (HDL-C), and increased very-low-density lipoprotein (VLDL) and triglyceride (TG) levels. It is one of the main threats for public health in the 21st century with its associated risk of cardiovascular disease. This condition affects a major chunk of mankind. International Diabetes Federation (IDF) estimated that around 20-25% of the adult population of the world has MetS. Several definitions have been put forward by different expert bodies leading to confusion. To overcome this, joint new statement of many expert group have been issued. Serum testosterone (T) has been shown to be associated with MetS. Several studies have shown a higher prevalence of MetS in subjects with low testosterone. There are also several studies showing a significant difference in serum T between those with MetS and those without. Serum T has also been shown to be associated with components of MetS and testosterone replacement therapy (TRT) improves various metabolic and anthropometric parameters in MetS. Patients with androgen deprivation for treatment of various cancers have also been reported to have higher prevalence of MetS. But the evidence of association is not sufficient evidence for the causation of MetS by low testosterone and long-term studies are needed to confirm whether T deficiency is the cause or is a feature of MetS.

The relationship between reduced testosterone, stimulated growth hormone secretion and increased carotid intima-media thickness in obese men

OBJECTIVE

Obesity is associated with reduced testosterone and growth hormone (GH). However, the interrelationship between these axes and their independent contributions to cardiovascular risk is unknown. The objectives of this study were to determine (1) the association between testosterone and GH in obesity, (2) whether excess adiposity mediates this association and (3) the relative contribution of reduced testosterone and GH to increased carotid intima-media thickness (cIMT) in obesity.

DESIGN

Fifty obese men were studied with GH-releasing hormone-arginine testing, and morning free testosterone (FT) was measured by equilibrium dialysis. Metabolic, anthropometric and cardiovascular risk indices, including cIMT were measured. Twenty-six normal weight men served as controls.

RESULTS

Obese subjects demonstrated lower mean (±SEM) peak stimulated GH (5·9 ± 0·6 vs 36·4 ± 3·9 μg/l; P < 0·0001) and FT (0·41 ± 0·03 vs 0·56 ± 0·03 nmol/l; P = 0·0005) compared to controls. GH was significantly associated with FT (r = +0·44; P < 0·0001) and both were inversely related to visceral adipose tissue (VAT) (GH: r = -0·65; P < 0·0001; FT: r = -0·51; P < 0·0001). In multivariate regression analysis controlling for VAT, FT was no longer related to GH. Both GH and FT were associated with cIMT in univariate analysis. However, in multivariate modelling including traditional cardiovascular risk markers, GH (β = 0·003; P = 0·04) but not FT (P = 0·35) was associated with cIMT.

CONCLUSIONS

These results demonstrate a strong relationship between FT and GH in obesity and suggest that this relationship is more a function of excess adiposity rather than a direct relationship. While reduced FT and GH are both related to increased cIMT, the relationship with reduced GH remains significant controlling for reduced FT and traditional cardiovascular disease risk markers.

Testosterone and the metabolic syndrome

Metabolic syndrome and testosterone deficiency in men are closely Linked. Epidemiological studies have shown that Low testosterone Levels are associated with obesity, insulin resistance and an adverse Lipid profile in men. Conversely in men with metabolic syndrome and type 2 diabetes have a high prevalence of hypogonadism. Metabolic syndrome and Low testosterone status are both independently associated with increased all-cause and cardiovascular mortality. Observational and experimental data suggest that physiological replacement of testosterone produces improvement in insulin resistance, obesity, dyslipidae-mia and sexual dysfunction along with improved quality of Life. However, there are no Long-term interventional studies to assess the effect of testosterone replacement on mortality in men with Low testosterone Levels. This article reviews the observational and interventional clinical data in relation to testosterone and metabolic syndrome.

Risk factors, prevention and early detection of prostate cancer

Approximately one in six men in the United States will develop prostate cancer during their lifetime. Genetic and environmental variables play a role in determining prostate cancer risk. This article highlights the latest evidence regarding the risk factors for prostate cancer. The current screening strategies using prostate-specific antigen and digital rectal examination are also discussed, as well as the limitations of these protocols and potential methods for improving early detection.

Lifestyle choices, diet, and insulin sensitizers in polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is significantly affected by environmental regulators impacting on genetic predisposition. Lifestyle changes can significantly modulate the phenotype of this disease. Diet, exercise, smoking, stress, and other factors adversely affect reproductive outcomes in PCOS. These influences can be modulated by structure change in an individual or group. Lifestyle choices should be discussed in this group of patients. The role of insulin sensitizers, including metformin, has still to be determined in this condition.

Obesity and polycystic ovary syndrome

The aetiology of Polycystic Ovary Syndrome (PCOS) is complex and multifactorial. There is much evidence, however, to suggest that adipose tissue plays an important role in the development and maintenance of PCOS pathology. There is a close correlation between adiposity and symptom severity in women with PCOS, and even modest reductions in weight generally translate into significant improvements in menstrual regularity, fertility and hyperandrogenic features. This review article considers the various mechanisms that might underlie this link between excess adiposity and PCOS - including the effects of differential insulin sensitivity, abnormal steroid hormone metabolism and adipocytokine secretion. Greater attention to the therapeutic options available to reduce the impact of excess adiposity on ovarian and metabolic function is essential to the management of PCOS.

Review of nonsurgical and surgical treatment and the role of insulin-sensitizing agents in the management of infertile women with polycystic ovary syndrome

OBJECTIVES

To review the nonsurgical and surgical treatment and the role of insulin-sensitizing agents in the management of anovulatory infertile women with polycystic ovary syndrome (PCOS).

MATERIALS AND METHODS

The search term of subfertile women with anovulation and PCOS was used for identification of randomized controlled trials. Nonrandomized controlled studies were identified through computer MEDLINE and EMBASE searches for the years 1980-2002.

RESULTS

For obese PCOS women weight loss of > 5% of pretreatment weight restores menstrual regularity in 89%, of whom 30% achieved spontaneous pregnancy. It was estimated that 75-80% of anovulatory PCOS women will respond to clomiphene citrate (CC) and 35-50% will achieve pregnancy. For CC-resistant PCOS women (20-25%), CC + metformin (1.5 g/day) for 3-6 months has a 70% chance of restoration of regular menses and ovulation, and a 23% chance of pregnancy. Laparoscopic ovarian drilling (LOD) can be offered to CC-resistant PCOS women. There was no statistically significant difference in the ovulation rate following LOD with electrocoagulation and laser [83% vs. 77.5%; odds ratio (OR) 1.4; 95% CI 0.9-2.1], while there was a significantly higher cumulative pregnancy rate at 12 months after surgery (65% vs. 54.5%; OR 1.5; 95% CI 1.1-2.1).

CONCLUSION

Diet and exercise followed by CC should be used for nonsurgical ovulation induction. For CC-resistant PCOS women, metformin may be included in a stepwise approach before a surgical approach. LOD with electrocautery is superior to laser drilling and gonadotropin therapy.

Resumption of fertility with diet in overweight women

In young women being overweight appears to be one of the major and still neglected causes of subfertility. Not only the excessive amount but also the distribution of body fat is clearly related to loss of fertility. The mechanism through which obesity impairs ovulation and fertility is largely unknown, but it is well known that being overweight lowers the concentration of sex hormone binding globulin and increases androgen and insulin secretion and insulin resistance. These high concentrations of androgen and insulin in turn are important factors in the preferential abnormal localization of body fat. In addition, ovulation induction or ovarian stimulation in overweight women is a not easy task, since these patients are often unresponsive to the stimulatory drugs and, in addition, have a higher rate of miscarriages. Weight reduction improves these patients' biochemical indices and fertility rates. The spontaneous pregnancy rate can be expected to be around 30%, but an additional 40-50% drug-induced pregnancy rate can be achieved with a 10-15% weight loss. Drugs increasing insulin sensitivity also improve spontaneous ovulation and fertility in obese women but still need to be tested in larger controlled trials. In conclusion, appropriate counselling about weight reduction through diets and exercise can restore both health and fertility, avoiding much frustration, and saving time and money.

Polycystic ovarian syndrome (PCOS) and insulin resistance

OBJECTIVES

Polycystic ovary syndrome (PCOS) presents a high risk of developing type 2 diabetes mellitus. We studied a group of women with PCOS and evaluated this defect in insulin action.

METHODS

The study population consisted of nine PCOS women, six obese type 2 diabetic patients, and five controls whose body mass index (BMI) was similar to that of the nine PCOS women. The 75-g oral glucose tolerance test (OGTT) and the hyperinsulinemic euglycemic glucose clamp test were performed. Clinical characteristics and the metabolic profiles, including the insulin sensitivity index (ISI), were compared.

RESULTS

PCOS women showed significantly elevated insulin responses during OGTT, but their blood glucose levels were comparable with the controls. The subjects with PCOS had more insulin resistance than the other groups. There was no difference among the groups in terms of clinical characteristics and metabolic profiles, except age, luteinzing hormone (LH), testosterone, and sex hormone binding globulin (SHBG).

CONCLUSION

We conclude that PCOS women have significant insulin resistance which is independent of adiposity.

Androgens and abdominal obesity

Central or visceral obesity is recognized as a main risk factor for cardiovascular disease and type 2 diabetes mellitus. The co-existence of visceral obesity, increased blood lipid levels, hypertension and impaired glucose tolerance defines the metabolic syndrome that today is widely recognized as one of the prime factors behind cardiovascular morbidity and mortality. Endocrine disorders such as insulinoma, hypothyroidism and hypercortisolism are known to cause obesity. However, it is only hypercortisolism that is associated with increased abdominal fat accumulation. Recently, new findings have shed light on subtle endocrinopathies that are prevalent in individuals presenting with the metabolic syndrome. Such derangements are of borderline character and often fall within the normal reference range. Intervention studies demonstrate that correction of relative hypogonadism in men with visceral obesity and other manifestations of the metabolic syndrome seem to decrease the abdominal fat mass and reverse the glucose intolerance, as well as lipoprotein abnormalities in the serum. Further analysis of the underlying mechanism has also disclosed a regulatory role for testosterone in counteracting visceral fat accumulation. Longitudinal epidemiological data demonstrates that relatively low testosterone levels are a risk factor for development of visceral obesity. The primary event that triggers the initial development of visceral obesity is not known, but it seems plausible that increased activity in the hypothalamus-pituitary-adrenal axis can be of major importance.

The effect of a pure antiandrogen receptor blocker, flutamide, on the lipid profile in the polycystic ovary syndrome

Polycystic ovary syndrome (PCOS) is one of the most common endocrinopathies affecting women of reproductive age; it is associated with hyperandrogenism, hyperinsulinemia, and dyslipidemia. This study was designed to assess the long term effects of a pure androgen receptor blocker, flutamide, on the lipid profile in women with PCOS and to examine the possible mechanisms by which androgens may exert their influence. Seventeen women with PCOS (10 obese and 7 lean) were studied. All subjects received a 12-week course of oral flutamide (500 mg/day). The baseline and posttreatment evaluations included lipid profile, androgen levels, insulin sensitivity, and serum catecholamine determinations. The primary outcome was the change in the ratio of low density lipoproteins (LDL) to high density lipoproteins (HDL). Treatment with flutamide was associated with a significant decrease in the LDL/HDL ratio by 23% (P = 0.005), in total cholesterol by 18% (P < 0.0001), in LDL by 13% (P = 0.002), and in triglycerides by 23% (P = 0.002). Flutamide treatment was also associated with a trend toward an increase in HDL (by 14%; P = 0.14). The effects on lipid profile were found regardless of obesity and were not associated with a change in weight. Furthermore, actions of flutamide on lipid metabolism were not associated with significant changes in circulating adrenaline or noradrenaline, glucose metabolism, or insulin sensitivity. This report has demonstrated for the first time that treatment with the pure antiandrogen, flutamide, may improve the lipid profile and that this effect may be due to direct inhibition of androgenic actions.

Role of opioid tone in the pathophysiology of hyperinsulinemia and insulin resistance in polycystic ovarian disease

Hyperinsulinemia secondary to a poorly characterized disorder of insulin action is a feature of polycystic ovarian disease (PCOD). On the other hand, being generally admitted that opioids may play a role in glycoregulation and that opioid tone is altered in PCOD, an involvement of the opioids in determining the hyperinsulinemia of PCOD patients could be suggested. The aim of this study was to evaluate the effect of a chronic opioid blockade on insulin metabolism and peripheral insulin sensitivity in PCOD hyperinsulinemic patients. Twenty-three women with PCOD were studied. An oral glucose tolerance test (OGTT) and a clamp study were performed at baseline (during the follicular phase) and after 6 weeks of naltrexone administration (50 mg/d orally). Based on the insulinemic response to the OGTT, 16 women were classified as hyperinsulinemic and seven as normoinsulinemic. Naltrexone treatment significantly reduced fasting (P < .05) and area under the curve (AUC) (P < .02) plasma insulin levels only in the hyperinsulinemic group. Moreover, hyperinsulinemic patients showed similar C-peptide incremental areas after naltrexone treatment, whereas in the same patients the fractional hepatic insulin extraction calculated from the incremental areas of insulin and C-peptide was found to be increased after chronic opioid blockade by naltrexone. For peripheral insulin sensitivity, the hyperinsulinemic group showed significantly lower (P < .01) total-body glucose utilization (M) compared with the normoinsulinemic group. No change in the M value was found after treatment in both groups. These data suggest that the insulin sensitivity and hyperinsulinemia after an OGTT are two distinct deranged features of the insulin disorder of PCOD patients.

Diagnosis and therapy of hyperandrogenism

Diagnostic categories in hyperandrogenism include polycystic ovary syndrome (PCOS) and its variants, adrenal and ovarian steroidogenic enzyme deficiencies, adrenal and ovarian androgen secreting tumours and other endocrine disorders such as hyperprolactinaemia, Cushing syndrome and acromegaly. About 95% of hyperandrogenic women will have PCOS. Endometrial hyperplasia can be prevented in hyperandrogenic, anovulatory women by the oral contraceptive pill or progestins. Hirsutism is best treated by a combination of the oral contraceptive pill and an anti-androgen. The first line of therapy for ovulation induction is clomiphene citrate, with human menopausal gonadotrophins (hMG) or laparoscopic ovulation induction reserved for clomiphene failures. hMG together with gonadotrophin-releasing hormone agonist may decrease the risk of spontaneous abortion following ovulation induction in PCOS. Weight loss should be vigorously encouraged to ameliorate the metabolic consequences of PCOS.

Disturbances in insulin secretion and sensitivity in women with the polycystic ovary syndrome

Insulin resistance, defined as a diminished effect of a given dose of insulin on glucose homeostasis, is a highly prevalent feature of women with PCOS. Insulin resistance in PCOS is closely associated with an increase in truncal-abdominal fat mass, elevated free fatty acid levels, increased androgens, particularly free testosterone through reduced SHBG levels, and anovulation. The causes for insulin resistance in PCOS are still unknown. One line of evidence suggests that an increase in truncal-abdominal fat mass and subsequently increased free fatty acid levels induce insulin resistance in women with PCOS. Increased effects of corticosteroids and a relative reduction in oestrogen and progesterone seem to be involved in the aberrant body fat distribution. Conversely, there are also results supporting primary, genetic target cell defects as a cause of insulin resistance in PCOS. An explanation for these seemingly contradictory results could be that the group of women with PCOS is heterogeneous with respect to the primary event in carbohydrate/insulin disturbances. Also insulin secretion in PCOS is characterized by heterogeneity. At one end of the spectrum is a large subgroup of mainly obese women with reduced insulin secretion, which appears to result from failure of the beta cells to compensate for insulin resistance in susceptible women, resulting in glucose intolerance and NIDDM. In the insulin-resistant patients with normal glucose tolerance, most of the hyperinsulinaemia is probably due to secondarily increased insulin secretion and decreased insulin degradation. However, a component of the increased first-phase insulin release is not due to measurable insulin resistance. Notably, this is also found in lean women with normal insulin sensitivity, and is not reversed after weight reduction, in contrast to the findings for insulin resistance. The implications of this enhanced insulin release are not fully clear, but it may tentatively be associated with carbohydrate craving and subsequently increased risks for development of obesity and insulin resistance. It may represent a primary disturbance of insulin secretion in PCOS or may be associated with the perturbed steroid balance in anovulation. The insulin-androgen connection in PCOS appears to be amplified by several different mechanisms, notably in both directions, the initiating event probably varying between individuals. Thus insulin increases the biological availability of potent steroids, primarily testosterone, through the suppression of SHBG synthesis. Insulin is also involved as a progonadotrophin in ovarian steroidogenesis, with the possible net result of interfering with ovulation and/or increasing ovarian androgen production in states of hyperinsulinaemia. Conversely, testosterone may indirectly contribute to insulin resistance through facilitating free fatty acid release from abdominal fat, but perhaps also through direct muscular effects at higher serum levels. It seems likely that this constitution, presumably genetic, would provide evolutionary advantages in times of limited nutrition, given the energy-saving effects of insulin resistance. Hypothetically, hyperinsulinaemia (primary) could provide a stimulus to ensure intake of nourishment, but unlimited food supplies could in some cases initiate a vicious 'anabolic' circle, in which several of the proposed amplifying mechanisms between insulin and androgens--in both directions--could take part.

The relation of body size to plasma levels of estrogens and androgens in premenopausal women (Maryland, United States)

We analyzed data from a cross-sectional study of 107 premenopausal women to evaluate the relations of height, weight, and body mass index (BMI) with plasma hormone levels. Participants were 20- to 40-year old women residing in Maryland (United States), whose reported menstrual cycle lengths were not more than 35 days and whose measured weights for height were 85 to 130 percent of 'desirable' based on 1983 Metropolitan Life Insurance tables. Fasting blood specimens were collected on each of days 5-7, 12-15, and 21-23 of every participant's menstrual cycle and pooled to create follicular, midcycle, and luteal phase samples, respectively, for analysis. Adjusted for age, taller women had significantly higher follicular-phase plasma-estradiol levels (percent difference/cm = 1.5, 95 percent confidence interval [CI] = 0.3-2.7, and heavier women had significantly lower plasma sex-hormone binding globulin (SHBG) levels averaged across the menstrual cycle phases (percent difference/kg = -1.2; CI = -1.9-(-0.6). Body weight within the range studied, however, was not related significantly to the concentration of SHBG-bound estradiol during any phase of the menstrual cycle. The results of this cross-sectional study suggest a possible mechanism by which height may influence breast cancer risk.

The independent effects of polycystic ovary syndrome and obesity on serum concentrations of gonadotrophins and sex steroids in premenopausal women

OBJECTIVE

To investigate the basal levels of gonadotrophins and sex steroids, with special reference to the effects of obesity and body fat distribution, in premenopausal women, both those with polycystic ovary syndrome (PCOS) and those with normal ovaries and regular menstrual cycles.

DESIGN

Cross-sectional study. The separate effects of obesity (and body fat distribution and fasting insulin levels) and PCOS on endocrine variables were evaluated by means of analysis of covariance.

PATIENTS

Sixty-seven women with anovulatory menstrual cycles and polycystic ovaries according to ultrasonography and 59 women with normal ovaries and regular cycles, both groups covering a wide range of body mass index (BMI, PCOS, 17.6-37.4, mean 25.7 kg/m2; controls, 18.8-40.9, mean 25.1 kg/m2).

MEASUREMENTS

Serum levels of gonadotrophins, sex steroid hormones, prolactin and GH obtained in the early follicular phase in the controls, fasting insulin levels, anthropometric measures (BMI, skinfolds, waist hip ratio).

RESULTS

Mean serum concentrations of LH, androstenedione, testosterone, the free androgen index (FAI; all P < 0.0001) and DHEAS (P < 0.01) were higher, and serum FSH (P < 0.01) and serum SHBG levels lower (P < 0.0001), in the PCOS group than in the controls. Women with PCOS had a more pronounced upper body fat distribution and higher fasting insulin levels than the controls. Independent of PCOS, BMI was positively associated with serum levels of FSH (P < 0.001) and negatively with levels of LH (P < 0.05), LH/FSH ratio (P < 0.0001), SHBG (P < 0.0001) and androstenedione (P < 0.01), whereas for levels of testosterone, FAI and DHEAS the impact of obesity differed significantly between the groups. Thus, in the PCOS group, testosterone levels (P < 0.05) and the FAI (P < 0.001) were positively associated with BMI, whereas they were constant throughout the entire range of BMI in the controls. DHEAS levels were positively associated with BMI in the PCOS group (P < 0.05) and negatively in the controls (P < 0.01). Measures of upper body fat were related to testosterone and FAI levels, independent of BMI.

CONCLUSIONS

Lower FSH levels were found in women with PCOS than during the early follicular phase of normally ovulating women, suggesting a role in anovulation in PCOS. Obesity itself exerted effects on endocrine variables, with the net result of a reduced LH/FSH ratio and lower serum levels of androstenedione and SHBG in both groups; obesity was associated with increased levels of DHEAS, testosterone and FAI exclusively in the women with PCOS. The results underline the endocrine impact of obesity and body fat distribution and the necessity of applying reference values of BMI matched subjects when establishing the endocrine profile of women with PCOS.

Body fat distribution has weight-independent effects on clinical, hormonal, and metabolic features of women with polycystic ovary syndrome

This study was performed to investigate whether different patterns of body fat distribution may have distinct effects on the clinical, hormonal, and metabolic features of women with clinical hyperandrogenism such as polycystic ovary syndrome (PCOS). Ninety-seven consecutive women with PCOS were included in the study after assessment of gynecological and obesity history and careful clinical examination. Women were divided into three tertile groups based on the waist to hip ratio (WHR). Those with peripheral body fat distribution (P-BFD) had a WHR of less than 0.80, those with intermediate body fat distribution (I-BFD) had a WHR of 0.81 to 0.90, and those with abdominal body fat distribution (A-BFD) had a WHR exceeding 0.90. Baseline blood and urine samples were obtained for several hormone and lipid determinations, and the response of glucose, insulin, and C-peptide to a glucose oral challenge (75 g) was investigated. In the PCOS group, WHR values were higher than those used to define P-BFD and A-BFD in the normal female population. As WHR values increased, a significantly greater prevalence of obesity and acanthosis nigricans and a lower prevalence of acne was present. No significant differences were present in any of the other clinical features between the three groups. Ovarian morphology and volumes were similar in all groups.(ABSTRACT TRUNCATED AT 250 WORDS)